Non-Patent Documents 1 and 2 and Patent Document 1 propose a silicon photonics interface in which a silicon optical waveguide is connected to a resin optical waveguide with low loss and at low cost. The silicon optical waveguide referred to in the present Description has a core-clad structure that functions as a (single-mode) optical waveguide formed on a silicon chip.
FIG. 3 is a perspective view illustrating a configuration example of such a silicon photonics interface and FIG. 4 is a side view thereof.
In a resin optical waveguide chip 300 illustrated in FIGS. 3 and 4, one or a plurality of resin optical waveguides 310 are formed. At one end side of the resin optical waveguide chip 300, the resin optical waveguide(s) 310 is(are) connected to a silicon optical waveguide (not illustrated) formed on a silicon optical waveguide chip 200. Another end side of the resin optical waveguide chip 300 is housed in a connector 100.
FIG. 5 is a perspective view illustrating a configuration example of the resin optical waveguide to be used for the above purpose.
The resin optical waveguide 310 illustrated in FIG. 5 has an under cladding 330 and an over cladding 340 provided around a core 320. However, the tip of the side with which the silicon optical waveguide (not illustrated) formed on the silicon optical waveguide chip 200 is to be connected in FIGS. 3 and 4 has no over cladding 340 provided, and forms a core-exposed section 350 where the core 320 is exposed to the outside.
FIG. 6 is a cross-sectional view illustrating a connecting part between the silicon optical waveguide 210 and the resin optical waveguide 310 in the silicon photonics interface illustrated in FIGS. 3 and 4. The resin optical waveguide 310 is the resin optical waveguide 310 illustrated in FIG. 5. In FIG. 6, the silicon optical waveguide 210 and the resin optical waveguide 310 are connected by using an epoxy resin in a state that the core 320 of the resin optical waveguide 310 faces to the silicon optical waveguide 210.
FIG. 7 is a schematic view for explaining light propagation in the silicon photonics interface illustrated in FIGS. 3 and 4. In FIG. 7, light is propagated from a core 220 of the silicon optical waveguide 210 to the core 320 exposed at the tip of the resin optical waveguide 310 by adiabatic coupling. Then, the light is propagated from the core 320 of the resin optical waveguide 310 to a core 140 of an optical fiber 130.